If no value as new entry then
Condition Type:Value of Item/Column in Expression 1 is NOT Null Expression1 : P17_NWM_DOC_ID
or as you want the condtion mode.
Condition Type:Value of Item/Column in Expression 1 Is Null Expression1 : P17_NWM_DOC_ID
Is there any way to assign the interactive report query column to link with hidden item so that hidden item can have the same value as interactive report column.No, If you just want to enable/disable buttons based on whether user has changed something or not, then you can do it with simple JS or jQuery.